As most of Leslie's relations were engaged in rural affairs, it is probable that he himself was originally destined for the same occupation. As is the case with boys in many parts of the Lowlands of Scotland, he attended school during the winter months, and kept the cattle in the summer, though the near vicinity of the school enabled him to attend partially all the year round.

By this means the chain of his early studies was never broken; and probably his rural occupation during part of the summer days was in all respects of considerable advantage. To his physical constitution it unquestionably added strength, and we are inclined to think that it gave to his mind much more vigor and elasticity than if he had had nothing to attend to but scholastic exercises. The mind must be formed, and if it is to be a philosophical and by consequence an inventive one, we suspect it must in all cases form itself; and therefore, if we were to point out the ladder by which the eminence of knowledge were to be climbed, we should place time to form the mind, apart from all didactic education, and circumstances under which to form it, as among the most essential steps.

Of the necessity of this, we have demonstration in the case of Mr. Leslie; and we state, daring any contradiction, that had the boy been mewed up constantly within the four walls of a school-room, or left to gossip with other boys in his hours of play, the philosopher would not have been what he is. There is a flow and a freshness in the writings of Leslie-a familiarity with nature at all its points, and an appreciation of all its beauties, which tells more, and breathes more of the green slopes of Largo Law, the cheerful scenery around, and the glittering expanse of the Firth of Forth gliding off into the eastern sea, than of the air of any school that ever was built; and we would not, and we are sure none of the numerous readers of his writings would, exchange it for the cold pedantry of all the scholastic institutions that ever existed.

Had Leslie been deprived of his time and his temptations to exercise his own powers in studying the phenomena of nature, he might have been a linguist, a mathematician, or a student in any single department of science; but to the circumstances in which he was placed he must have been in a great measure indebted for his universality of application. The appearances of the heavens, the changes of the weather, the succession of the seasons, the features of the land, and the phenomena of the ocean, were around him from a commanding station, and they were so grouped that a youth of ardent mind could hardly avoid thinking of them, and speculating about and wishing to know their causes. Hence, when his more scholastic instruction, and his extensive acquaintance with men of information and with books put him in possession of the theories, he was instantly enabled to refer these to facts with which he was already familiar. So that Leslie ought to be considered as a man enjoying the advantage of a double education,—a knowledge of phenomena, which is wholly his own, and which he would have enjoyed whether he had been a farmer or a philosopher; and a knowledge of philosophy, usually so called, which he acquired from attending college, from reading books, from extensive intercourse with learned and eminent men, from a long and arduous course of personal observation and experiment, and from much practice in the profession of teaching.

We have mentioned that Leslie's introduction to this second species of information was accidental, and the accident is worth relating. Engaged, as has been previously mentioned, till about, we believe, his thirteenth or fourteenth year, he had made considerable progress in all the branches taught at the village school, which, as the parish is rich and populous, ranks a parish school of the first class, and generally possesses an able teacher.

But it appears that Leslie had a more extended desire of knowledge than that which the school afforded

him. The field on which he tended the cattle was for the most part hedged in, so that his attendance was more a necessity of being in the fields than an employment. There are always books in a Scotch farm-house, and additional ones can always be borrowed in a Scotch village. Young Leslie generally had his book with him, not his class-book in order to con his lessons, for that cost him little trouble, but a book which he might read for the information of the facts, or the amusement of the story, as it might happen. Among these there was a copy of Simson's Euclid, upon which Leslie commenced his career as a mathematician. Unprovided with other apparatus for the drawing of his diagrams, he began at the beginning, by having recourse to the abacus of the anci、nts,—he powdered the footpath by the hedge-side with sand, delineated his figures thereon with his finger; and, closing his book, went over his demonstrations,

In the early part of his course, and when he was passing that serious bridge, called the "bridge of asses," because they alone are unable to cross it, the minister of the parish was on the other side of the tall hawthorn hedge, also engaged in study. The minister of Largo was kind and conversational, and in the absence of a local newspaper he performed not a few of its functions. He held forth passing well when he had got a sermon and was in the pulpit; but a new one was the labors of Hercules.

So,

to bring his bumps into proper action, he used to pace up and down the side of the hedge above-mentioned; and it must be allowed that if agitation was his object, the place was well chosen. The slope was very considerable, not less than five-and-twenty or thirty degrees; and as the ventral region of the minister was a little ponderous, and his legs none of the longest, when he went dodge, dodge down the hill, the different parts of his cranial or ganization were ground and triturated against each other, in the same way as the Dutch make marbles, and the

dust of words was produced ́in abun- ́ dance. Then as he went up the hill, the upper part of the cranial organs (which also were none of the lightest) pressed out, in the form of sentences, the words which had been elaborated during the descent. Physically and mentally, this was rather hard labor; and the minister had often to stand and take his breath.

During one of these pauses he was startled by muttered sounds from the other side of the hedge; and listening, he could hear the words "angle," "triangle," "two sides of the one equal to two sides of the other," and A, B, C, mingled with words and sentences. St. Andrew's, where he had disciplined, flashed upon his mind : "That must be mathematics!" quoth the minister of Largo. He listened with more attention; and as the recollections of St. Andrew's came more vivid to his memory, he ascertained that the lesson was in very deed the fifth proposition of Euclid's first book, while his own eyes through the hedge informed him that the student was none other than John, or, as he was then called, Jock Leslie, conquering that in solitude and without instructer, which the minister himself had never been able to overcome amid all the science and stimuli of St. Andrew's.

The minister was more than delighted; and though it cut his sermon in the middle, and rendered not merely the connection but the second half doubtful, down he trudged to communicate the discovery to Leslie's father. "I have something important to communicate," said the minister of Largo. Mr. Leslie turned, and looked grave-for he was an elder of the kirk, and sometimes, though not often, they had inquiries and rebukings "anent sin ;" but he spake not. The minister laid hold of his button, and with a beaminess of visage, which convinced Mr. Leslie that there was no sin in the case, uttered, at half-minute time, these words " Mr. Lessels, I am sure your son Jock's a genus." "What," said Mr. Leslie, rather

:

hastily," has he been lattin the kye eat the corn?" "Very far from it, Mr. Lessels," replied the minister, "he has a genus for mathematics, and you must just send him to St. Andrew's." The advice of the minister was complied with: Leslie went to St. Andrew's the very next autumn, was successful in his classes, prudent in his finances, and gave sufficient evidence that he would not turn back in the path to eminence on which he had entered. Not very long after the completion of his studies, he became tutor to the Wedgewoods, which gave him much knowledge of the world both at home and abroad while in that employment, and afforded him an annuity for life which, independently of any other provision, would have enabled him to pursue those experimental inquiries to which he had got an additional stimulus from the scientific owners of Etruria. Soon after this he went into philosophical retirement in his brother's house at Largo, where he performed a number of experiments, and made some of his neatest inventions. Along with his profundity he was playful; and sometimes took delight in astonishing the rustics and fishwomen with phantasmagoria, and other optical illusions, or startling them with electricity or galvanism. On account of this playfulness of disposition the elder Sibyls generally suspected that he was conversant with the black art; but the younger and better educated were incredulous on that point, and alleged that he was flesh and blood just like themselves.

Toward the close of the last century, Mr. Leslie was a candidate for the chair of natural philosophy in Glasgow, but he was unsuccessful, not from any want of qualification, but because he had been a good deal out of Scotland, and was consequently not so well known as some of the other candidates.

Want of success at Glasgow did not

On

in any degree damp Mr. Leslie's ardor in his philosophical studies. the other hand, he, if possible, pursued them with more assiduity and success; and, though he was chiefly among his apparatus in his retirement, his name became celebrated in the scientific world as one of the most ingenious and original of inquirers. His experimental inquiry on heat excited much attention, both on account of the ingenuity of the experiments, and the boldness of the conclusions. On the death of Professor Robinson, in 1805, and the subsequent promotion of Playfair to the chair of Natural Philosophy in Edinburgh, Leslie became a candidate for the Mathematical Professorship in that University; and, though the candidates were numerous, and several of them men of eminent talents, it was generally admitted that Leslie was entitled to the office. A violent outcry was raised against him by those who could not enter the lists with him in qualification, and yet were anxious to see it filled otherwise; but the result was a triumph to Leslie far greater than if the outcry had not been raised. When the scientific world was deprived of Playfair, in 1819, Mr. Leslie was promoted to the chair of Natural Philosophy as a matter of justice to his talents.

It is needless to enumerate either the inventions or the writings of Mr. Leslie; they are numerous, they are varied, and there is much spirit and novelty in them all. Subjects which appear at first sight the least imaginative, are by him clothed with the fascinations of fancy; and if there be occasionally apparent obscurities both in his lectures and his writings, these must be ascribed to the giant strides which he takes from one eminence to another without noticing the intermediate points, without which inferior men cannot proceed.